Unblock Messenger Call -

To unblock a Messenger call, you primarily need to remove the restriction or block placed on the specific contact within the app's settings. Unblocking a user restores their ability to message and call you instantly. How to Unblock Someone on Messenger (Mobile)

If the "Call" button is grayed out or you receive a "Message Not Sent" warning, it is a strong indicator that the other person has blocked you . In this case, you cannot unblock the call feature from your end; the other user must remove the block from their privacy settings. unblock messenger call